To understand the difference between the metabolism of the two isomeric derivatives of mirex (cis and trans 5, 10-dihydromirex) the tissue disposition, excretion, biotransformation and identification of metabolites will be studied in the laboratory rat. Preliminary data have indicated a significant difference between male and female rats in the metabolism of the cis and trans- isomers. The basic chemical studies will include synthesis of the isomers, isolation and identification of the metabolites, development of analytical methods for quantification and the determination of selected physical properties. To accomplish these goals various analytical techniques will be utilized including: gas chromatography/mass spectrometry; fourier transform infra-red spectroscopy; fourier transform nuclear magnetic resonance spectroscopy; electron capture gas chromatography; and, liquid scintillation spectrometry. A major aspect of the investigations will involve the use of radiolabelled compounds. 14C-labelled cis or trans 5,10-dihydromirex will be given to both male and female rats. Tissue disposition, and excretion of the isomers will be studied for up to 14 days. Excreta from the isomer dosed rats will be collected, extracted and metabolites isolated, quantified and identified. Other studies will involve both in vivo and in vitro biochemical studies in which the monooxygenases will be studied. These studies will provide a correlation between metabolism and the mixed function oxidases. The differences in metabolism between cis and trans 5, 10-dihydromirex offer a unique opportunity to study basic biotransformations. Data gained from these studies should provide a better understanding of the differences in metabolic potential between male and female vertebrates. These studies have implication in understanding the pharmacological and toxicological effects of an environmentally important class of insecticides.